Research links Vitamin D levels to effects on brain and social behaviour

New research from the US is suggesting that Vitamin D could influence levels of serotonin in the brain, leading to a direct effect on social behaviour associated with Autism Spectrum Disorder (ASD).

A team led by Professor Bruce Ames at the Children's Hospital Oakland Research Institute worked on a study that looked at how serotonin, oxytocin, and vasopressin - three brain hormones that affect social behaviour - are all activated by vitamin D.

“We present evidence that vitamin D hormone (calcitriol) activates the transcription of the serotonin-synthesizing gene tryptophan hydroxylase 2 (TPH2) in the brain at a vitamin D response element (VDRE) and represses the transcription of TPH1 in tissues outside the blood-brain barrier at a distinct VDRE suggesting a causal link between the sunshine vitamin, serotonin and autism,” stated Prof Ames.

The study was published in the FASEB Journal and the team is now calling for clinical trials to follow up their work.

Ames went on to suggest that adequate levels of vitamin D may be required to produce serotonin in the brain - where it shapes the structure and wiring of the brain, acts as a neurotransmitter, and affects social behaviour.

He also says that autism has previously been linked to low levels of serotonin in the brain and low vitamin D levels, but nothing had linked the two until now.

Ames believes that taking adequate vitamin D hormone levels during pregnancy, as well as nutritional intake of tryptophan and vitamin D during early childhood, “may have a critical influence on brain serotonin levels and, thus, on the structure and neural wiring of the brain.”

As part of the study, Ames and his team show that vitamin D activates the gene that makes the enzyme tryptophan hydroxylase 2 (TPH2), which in turn converts the essential amino acid tryptophan to serotonin in the brain.

They also point to evidence that the gene that makes the enzyme tryptophan hydroxylase 1 (TPH1) is inhibited by vitamin D, which subsequently halts the production of serotonin in the gut and other tissues.